This invention relates generally to data transmissions and more particularly to data transmissions that utilize multiple data transport protocols such as USB and IR data transport protocols.
Data transmission techniques for transmitting data from one device to another device, wherein the devices are physically proximal (e.g., in the same room, the same building, or within a few thousand feet) to one another, are known. Such data transmission techniques utilize a particular transport medium (e.g., radio frequency (RF), infrared (IR), fiber optics, and/or wires) and a particular data transport protocol. For example, data transmissions utilizing an IR transport medium may be processed in accordance with an IrDA specified slow or fast IR data transport protocol, Amplitude Shift Keying (ASK) data transport protocol, or pulse code modulation (PCM) data transport protocol. Correspondingly, each of the transport mediums may be defined in accordance with standardized data transport protocols.
One such standardized data transport protocol is the Universal Serial Bus (USB) protocol, which prescribes data transmissions via a USB port. As is known, current state of the art computers include a USB port enabling the computer to communicate with a device (e.g., another computer, a printer, backup tape drive, etc.) at a rate up to 12 Mega Bits per second (Mbps). For the devices to communicate, they must be coupled via a cable that is capable of supporting such high speed data. As is also known, high speed data cables require shielding and low active and passive impedances, which add to the cost of the cable (e.g., approximately $20US for a six foot cable from a commercial retailer). In addition, if the USB port is incorporated into a laptop computer, a transient user would need to carry a USB cable.
To reduce the impact of utilizing the USB port (i.e., its cost and need for a special cable), a proposal was introduced in 1997 entitled xe2x80x9cUniversal Serial Bus IrDA Bridge Device Definitionxe2x80x9d (hereinafter the USB/IrDA Device) that suggested replacing the USB cable with IR transceivers. The USB/IrDA Device was specified to include a USB device controller, USB interface firmware, USB/IrDA bridge device firmware, IrDA interface firmware, and an IrDA transceiver. In general, the USB/IrDA Device was to receive data from a host (e.g., a computer) in accordance with the USB data transport protocol. As such, the host packetizes the data and sends the packets to the USB/IrDA Device. Upon receiving the packets, the USB device controller reconstructs the data and, via the USB interface firmware, provides the reconstructed data to the USB IrDA bridge device firmware. The USB IrDA bridge device firmware processes the data in accordance with an IRDA data transport protocol (e.g., slow or fast IR) to produce a frame of IR data. The IR data is provided to the IrDA transceiver via the IrDA interface firmware.
An issue with the USB/IrDA Device is that it requires a microprocessor, microcontroller, or digital signal processor to efficiently perform the significant amount of processing. Currently, such microprocessors, microcontrollers, or digital signal processors cost as much, if not more, than the USB cable. Thus, a main benefit of the USB/IrDA Device, i.e., less cost than the USB cable, is lost.
Therefore, a need exists for a method and apparatus that overcomes the above mentioned limitations of USB cables and the USB/IrDA Device.